Can you identify these equations?

[Luxor123]

I have come across these equations elsewhere, but the context didn't give anything away about what they actually are. I assume they're both from a similar area, but that may not be necessarily true.

I guess they're physics equations because of the presence of Planck's constant and c (speed of light?)

 

[blue_leaf77]

That's Dirac equation of a charged particle in a vector potential $A$ and scalar potential $eA_0(x)$. I hope there are other members correcting me in case I am wrong or add something.

 

[Luxor123]

Thanks, is that just the top one, and is the bottom one involved as well? I had a look at Wikipedia and it seemed to involve gamma in some way, but it is well beyond my level of understanding.

 

[ShayanJ]

Thanks, is that just the top one, and is the bottom one involved as well? I had a look at Wikipedia and it seemed to involve gamma in some way, but it is well beyond my level of understanding.

About the top equation, I agree with blue_leaf77. The bottom one seems to be the definition of time-reversal operator to me where $\hat K$ is the complex conjugation operator.